CA2785700A1 - Steering drive system and skid steer vehicle equipped therewith - Google Patents
Steering drive system and skid steer vehicle equipped therewith Download PDFInfo
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- CA2785700A1 CA2785700A1 CA2785700A CA2785700A CA2785700A1 CA 2785700 A1 CA2785700 A1 CA 2785700A1 CA 2785700 A CA2785700 A CA 2785700A CA 2785700 A CA2785700 A CA 2785700A CA 2785700 A1 CA2785700 A1 CA 2785700A1
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- drive
- gear unit
- steering
- drives
- drive system
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
- B62D11/02—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides
- B62D11/06—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source
- B62D11/10—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source using gearings with differential power outputs on opposite sides, e.g. twin-differential or epicyclic gears
- B62D11/14—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source using gearings with differential power outputs on opposite sides, e.g. twin-differential or epicyclic gears differential power outputs being effected by additional power supply to one side, e.g. power originating from secondary power source
- B62D11/16—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source using gearings with differential power outputs on opposite sides, e.g. twin-differential or epicyclic gears differential power outputs being effected by additional power supply to one side, e.g. power originating from secondary power source the additional power supply being supplied mechanically
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19023—Plural power paths to and/or from gearing
- Y10T74/19051—Single driven plural drives
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Non-Deflectable Wheels, Steering Of Trailers, Or Other Steering (AREA)
- Retarders (AREA)
- Power Steering Mechanism (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
Abstract
The invention relates to a steering drive system (10) and a skid steer vehicle equipped therewith, wherein the steering drive system (10) comprises: a drive assembly (11) having a first and a second drive (11a, 11b), a summation gearbox (12) for summing driving torque of the drives (11a, 11b) to an output shaft (13c) of the summation gearbox (12), a first drive connecting device (14), by means of which the first drive (11a) is drivingly connected to a first input shaft (13b) of the summation gearbox (12), a second drive connecting device (15), by means of which the second drive (11b) is drivingly connected to a second input shaft (13a) of the summation gearbox (12), wherein the drive connecting devices (14, 15) are equipped such that none of the driving torque directed at the drives (11a, 11b) can be transmitted to the drives (11a, 11b) when a permanent drive connecting is established between the drives (11a, 11b) and the summation gearbox (12).
Description
STEERING DRIVE SYSTEM AND SKID STEER VEHICLE EQUIPPED THEREWITH
The invention is directed to a steering drive system for a skid steer vehicle and a skid steer vehicle, for example, a tracked vehicle, outfitted therewith.
Steering drive systems for skid steer vehicles in which a steering speed is superimposed on a translational traction drive for the vehicle are known from the prior art.
Of these, diverse configurations are known which either use an independent drive for each wheel side of the skid steer vehicle or in which traction drives are superimposed via a central drive unit using differentials.
Examples of steering drive systems of this kind are described in DE 24 46 727 Al and DE .2 009 255 Al.
Multi-circuit steering drive systems or steering drive systems offering steering drive redundancy are not currently known. Yet existing steering drive systems have the disadvantage that they cannot ensure a precise or unimpaired steerability of the vehicle in case of failure of a steering drive.
A very high expenditure on dimensioning, electronics and software is required in order to make cascaded electrical systems reliable in terms of system technology. Because of the large expenditure, it has not been possible heretofore to integrate any of these electric drives on a large scale in vehicles having a design-dependent maximum speed of over 52 km/h.
It is the object of the invention to provide a steering drive system, particularly a superposition steering drive system, for a skid steer vehicle, wherein the steering drive system ensures a precise emergency steering of the vehicle. The invention has the further object of providing a skid steer vehicle, particularly a tracked vehicle, which is outfitted with a steering drive system of this kind.
The above-stated objects are met by a steering drive system according to claim 1 and a skid steer vehicle according to claim 11. Further developments of the invention are defined in the dependent claims.
According to a first aspect of the invention, a steering drive system, particularly a superposition steering drive system, is provided for a skid steer vehicle, wherein the steering .
NYC_MIDT0WN\193998911 314127.000 drive system has: a drive arrangement having a first drive and a second drive which are constructed as separate units, a summing gear unit for summing respective driving torques of the two drives on an output shaft of the summing gear unit, a first drive connection device by means of which the first drive is drivingly connected to a first input shaft of the summing gear unit, and a second drive connection device by means of which the second drive is drivingly connected to a second input shaft of the summing gear unit, wherein the two drive connection devices are arranged in each instance such that no driving torque or back driving torque directed to the drives from the summing gear unit can be transmitted to the drives during a continuously produced drive connection between the drives and the summing gear unit.
Due to the fact that the invention provides two drives, particularly two drives which can be operated simultaneously, whose driving torques are summed by the summing gear unit on a common output shaft, then in the event of failure of one of the drives an emergency steering can be guaranteed by the other respective drive. In case of failure of a drive, a loss of torque for the drive remaining in operation owing to back driving on the inoperative drive is reliably prevented because no driving torque directed to the drives from the summing gear unit can be transmitted to the drives.
In cascaded multi-circuit steering, the drives would have to be overdimensioned. The solution suggested by the invention eliminates this problem through the gear ratio conditions in the summing gear unit. To turn (steer) a skid steer vehicle, a minimum turning torque is required. If there were two cascaded steering drives, for example, then in the event of failure of one drive the drive that is still functioning must apply twice the amount of torque to generate the required turning torque. In the solution according to the invention, the summing gear unit assists the still functioning drive while the second input shaft is inoperative and therefore makes the required turning torque available.
According to an embodiment form of the invention, the first drive and the second drive can be operable independently from one another by means of separate and mutually independent power sources such as, e.g., separate batteries or fuel cells in drives constructed as electric motors or, e.g., separate fuel tanks in drives constructed as combustion engines.
Accordingly, in an advantageous manner the operating reliability and the emergency steering function of the steering drive system are improved even more.
NYC _MI DTOWN\193998911314127.000 According to an embodiment form of the steering drive system according to the invention, the two drive connection devices are self-locking for driving torques directed from the summing gear unit to the drives.
This embodiment of the steering drive system according to the invention can be realized in a particularly simple and therefore economical manner. Further, a steering drive system designed in this way is especially operationally reliable and resistant to failure because the self-locking is triggered without separate signaling or actuating elements whenever driving torque or back drive torque is directed to the drives.
According to embodiment forms of the steering drive system according to the invention, the two drive connection devices each have toothed elements and/or a worm drive and/or a screw drive and/or an epicyclic gear unit.
These embodiments of the steering drive system according to the invention represent additional configurations which can be realized in a simple and therefore economical manner and which are resistant to failure.
According to an embodiment form of the steering drive system according to the invention, the first drive connection device has a first braking device which is arranged to firmly brake a drivetrain of the first drive, the second drive connection device has a second braking device which is arranged to firmly brake a drivetrain of the second drive, and speed detection means are provided for detecting respective driving speeds of the two drives, wherein the braking devices are each arranged to be selectively activated based on the driving speeds of the two drives and a differential speed determined therefrom.
The features according to this embodiment of the invention can be provided additionally or alternatively. The respective braking devices provide an alternative to, or redundancy of; the self-locking which can be controlled and integrated in a simple manner and which is therefore likewise economical. The speed detection means, e.g., contact-based or noncontacting speed sensors, are preferably arranged in the summing gear unit. Further, an electronic control unit can be provided which evaluates speed signals of the speed sensors and determines the differential speed and which is signal-coupled to the braking devices for controlling the latter (switching it on and off).
According to yet another embodiment form of the steering drive system according to the invention, the summing gear unit is a planetary gear unit.
NYC_MIDTOWN\1939989\1314127.000 This embodiment of the summing gear unit provides a technologically proven and reliable possibility for summing two drive outputs. Since there are many commercially available variants of planetary gear units, even standard gear units can be used if required, which further reduces costs and improves service-friendliness, particular with respect to repair times.
The first input shaft of the summing gear unit is preferably drivingly connected directly to a planet carrier of the summing gear unit, the second input shaft of the summing gear unit is drivingly connected directly to a sun gear of the summing gear unit, and the output shaft of the summing gear unit is drivingly connected directly to a ring gear of the summing gear unit.
According to a second aspect of the invention, a skid steer vehicle is provided, particularly a tracked vehicle, which has a steering drive system according to one or more or all of the embodiment forms according to the invention in any conceivable combination and a first steering differential, a second steering differential, a prime mover for realizing a translational drive of the vehicle, and a clutch element, wherein the prime mover is drivingly connected to both steering differentials, and wherein. the clutch element is drivingly connected to both steering differentials and also to the output shaft of the summing gear unit.
The steering differentials and the steering drive system preferably work together in such a way that the clutch element behaves in a neutral manner when the vehicle travels in a straight line, wherein the clutch element is preferably formed by a neutral shaft or zero shaft, and the steering differentials are preferably formed by a planetary gear unit, wherein the zero shaft is stationary when the vehicle drives in a straight line.
The invention will be described in more detail in the following with reference to preferred embodiment forms and the accompanying drawings.
Fig. 1 is a schematic view of a steering drive system of a skid steer vehicle according to the invention.
Fig. 1 shows a schematic view of a driving and steering system I of a skid steer vehicle (not shown in its entirety and not designated separately) constructed in the form of a tracked vehicle according to embodiment forms of the invention.
The skid steer vehicle has a steering drive system 10 and a traction drive system 20, wherein the steering drive system 10 is in a drive connection with the traction drive system 20 to influence the traction drive system 20.
NYC MIDTOWN\1939989\1 314127.000 The steering drive system 10 has a drive arrangement 11 having a first drive 11 a and a second drive 11 b, a summing gear unit 12 constructed as a planetary gear unit or epicyclic gear unit for summing respective driving torques of the two drives I Ia, l lb on an output shaft 13c of the summing gear unit 12, a first drive connection device 14 by means of which the first drive l la is drivingly connected to a first input shaft 13b of the summing gear unit 12, and a second drive connection device 15 by means of which the second drive 11 b is drivingly connected to a second input shaft 13a of the summing gear unit 12.
The first input shaft 13b of the summing gear unit 12 is drivingly connected directly to a planet carrier 12b of the summing gear unit 12, the second input shaft 13a of the summing gear unit 12 is drivingly connected directly to a sun gear 12a of the summing gear unit 12, and the output shaft 13c of the summing gear unit 12 is drivingly connected directly to a ring gear 12c of the summing gear unit 12.
According to embodiment forms of the invention, the first drive 11 a and the second drive I lb are formed, e.g., by an electric motor or a hydraulic motor.
The two drive connection devices 14, 15 are each arranged such that during a continuously produced drive connection (i.e., without the respective drives 1 I a, 11 b being severed or decoupled from the summing gear unit) between the drives l la, l lb and the summing gear unit 12, no driving torque directed to the drives 11a, 11 b from the summing gear unit 12 can be transmitted to the drives I I a, 1 lb.
More precisely stated: the first drive connection device 14 has toothed elements in the form of a self-locking worm drive 14a and a first braking device 14b which is arranged in a drivetrain of the first drive I1 a and in front of the worm drive 14a so that the first braking device 14b when correspondingly controlled can firmly brake the drivetrain of the first drive I I a.
Similarly, the second drive connection device 15 has toothed elements in the form of a self-locking worm drive 15a and a second braking device 15b which is arranged in a drivetrain of the second drive 11 b and in front of the worm drive 15a so that the second braking device 15b can firmly brake the drivetrain of the second drive 1 lb when controlled in a corresponding manner.
Further, the steering drive system 10 has speed detection means, not shown, in the summing gear unit in the form of noncontacting speed sensors for detecting respective driving speeds of the two drives. Further, the steering drive system 10 has an electronic NYC MIDTOWN\1939989\1314127.000 control unit (not shown) which evaluates speed signals of the speed sensors and determines a differential speed therebetween; the control unit is signal-coupled via signal lines, not shown, to the braking devices 14a, 15a for controlling (switching on/switching ofd the latter.
The control unit is configured by hardware and/or software to selectively activate the braking devices 14b, 15b based on their driving speeds and the differential speed so that if one of the drives 11 a, 1 lb fails, its associated braking device 14b or 15b is automatically activated or braked.
The traction drive system 20 has a first steering differential 21 constructed in the form of a planetary gear unit or epicyclic gear unit, a second steering differential 22 constructed in the form of a planetary gear unit or epicyclic gear unit, a prime mover 23, e.g., in the form of a combustion engine or hydraulic motor, for realizing a translational drive of the vehicle, and a clutch element 24 constructed as a zero shaft.
The prime mover 23 is drivingly connected via first input shafts 23a and 23b, respectively, directly to ring gears 21c and 22c, respectively, of the two steering differentials 21, 22. Respective planet carriers 21b and 22b of the two steering differentials 21, 22 are drivingly connected directly to a first driven shaft 25a and a second driven shaft 25b, respectively, for the translational traction drive.
A sun gear 21 a of the first steering differential 21 is drivingly connected via a second input shaft 26a of the first steering differential 21 and via two toothed wheels 26, 27 to a first toothed wheel 24a which is connected to the clutch element 24 so as to be fixed with respect to rotation relative to it. A sun gear 22a of the second steering differential 22 is drivingly connected via a second input shaft 28a of the second steering differential 22 and via a toothed wheel 28 to a second toothed wheel 24b which is connected to the clutch element 24 so as to be fixed with respect to rotation relative to it.
The second toothed wheel 24b which is connected to the clutch element 24 so as to be fixed with respect to rotation relative to it drivingly engages with a toothed wheel 16 which is connected to the output shaft 13c of the summing gear unit 12 so as to be fixed with respect to rotation relative to it.
Although not depicted in this way in Fig. 1, the braking devices 14b, 15b, the speed detection means and the electronic control unit can also be omitted according to embodiment forms of the invention.
NYC MIDTOWN1193998911 314127.000 The operation of the multi-circuit steering system according to embodiment forms of the invention will now be described referring to Fig. 1.
As can be seen from Fig. 1, the prime mover 23 drives into the steering differentials 21, 22 via the first input shafts 23a, 23b and the respective ring gears 21c, 22c. When the vehicle drives in a straight line, the prime mover 23 drives exclusively, the driving torque thereof being distributed to the two driven shafts 25a, 25b via the steering differentials 21, 22.
During synchronous running of the two driven shafts 25a, 25b, the clutch element 24 is stationary or behaves in a neutral manner. When the vehicle corners, a differential torque is generated by the drives 11 a, 11 b of the steering drive system 10, and this differential torque acts on the steering differentials 21, 22 via the drive connection devices 14, 15, via the summing gear unit 12, the toothed wheel 16 arranged on the output shaft 13c of the summing gear unit 12, the clutch element 24 and toothed wheels 26, 27, 28 arranged thereon, and toothed wheels 26, 27, 28 and generates different torques at the driven shafts 25a, 25b. The different torques at the driven shafts 25a, 25b generate a yaw moment which results in different speeds at the driven shafts 25a, 25b and a cornering movement of the vehicle.
The drives 11 a, 11 b of the steering drive system 10 are summed by the summing gear unit 12 in common on the output shaft Be and, therefore, on the toothed wheel 16 arranged thereon. In so doing, the two input shafts 13a, 13b of the summing gear unit 12 are mutually supported by one another with respect to torque.
In the event of failure of one of the drives 11 a, 11 b, this mutual torque-related support is canceled. In so doing, the load direction at the respective worm drive 14a or 15a changes direction, and this change in direction is automatically blocked by the self-locking effect of the worm drive 14a, 15a.
Due to the fixing of one of the input shafts 13a, 13b of the summing gear unit 12, the latter is functionally transformed into a reduction gear unit for the drive l la or 11 b that is still functioning. As a result of the gear ratio conditions in the summing gear unit 12, the toothed wheel 16 of the output shaft Be of the summing gear unit 12, which toothed wheel 16 is drivingly connected to the clutch element 24, is still acted upon by the same nominal torque in spite of the failure of one of the drives 11 a, 11 b.
Accordingly, the vehicle, which possibly needs a high yaw moment to overcome the transverse resistance forces, remains steerable. The failure of one of the drives 1 l a, l l b of NYC MIDTOWN\1939989\1 314127.000 the steering drive system 10 can possibly lead to a reduction in the achievable steering performance, but the vehicle remains steerable.
A firm braking of the inoperative drive l la or 1 lb can also be ensured in addition to or as an alternative to the respective worm drive 14a, 15a by the respective braking device 14b or 15b (if provided). In addition, according to embodiment forms of the invention, secondary states of the drives 11 a, 11 b, e.g., a pressure drop in an inoperative hydrostatic drive 11a or 11 b or the respective speeds and differential speed thereof (as described above), can be used as braking initiators.
NYC MIDTOWN\1939989\1314127.000 Reference Numerals 1 driving and steering system steering drive system 11 drive arrangement h a drive 11 b drive 12 summing gear unit 12a sun gear 12b planet carrier 12c ring gear 13a input shaft 13b input shaft 13c output shaft 14 drive connection device 14a worm drive 14b braking device drive connection device 15a worm drive 15b braking device 16 toothed wheel traction drive system 21 steering differential 21a sun gear 21b planet carrier 21c ring gear 22 steering differential 22a sun gear 22b planet carrier 22c ring gear 23 prime mover 23a input shaft 23b input shaft 24 clutch element NYC-MIDTOWN1193998911 314127.000 24a toothed wheel 24b toothed wheel 25a driven shaft 25b driven shaft 26 toothed wheel 26a input shaft 27 toothed wheel 28 toothed wheel 28a input shaft NYC MIDTOWN\193998911 314127.000
The invention is directed to a steering drive system for a skid steer vehicle and a skid steer vehicle, for example, a tracked vehicle, outfitted therewith.
Steering drive systems for skid steer vehicles in which a steering speed is superimposed on a translational traction drive for the vehicle are known from the prior art.
Of these, diverse configurations are known which either use an independent drive for each wheel side of the skid steer vehicle or in which traction drives are superimposed via a central drive unit using differentials.
Examples of steering drive systems of this kind are described in DE 24 46 727 Al and DE .2 009 255 Al.
Multi-circuit steering drive systems or steering drive systems offering steering drive redundancy are not currently known. Yet existing steering drive systems have the disadvantage that they cannot ensure a precise or unimpaired steerability of the vehicle in case of failure of a steering drive.
A very high expenditure on dimensioning, electronics and software is required in order to make cascaded electrical systems reliable in terms of system technology. Because of the large expenditure, it has not been possible heretofore to integrate any of these electric drives on a large scale in vehicles having a design-dependent maximum speed of over 52 km/h.
It is the object of the invention to provide a steering drive system, particularly a superposition steering drive system, for a skid steer vehicle, wherein the steering drive system ensures a precise emergency steering of the vehicle. The invention has the further object of providing a skid steer vehicle, particularly a tracked vehicle, which is outfitted with a steering drive system of this kind.
The above-stated objects are met by a steering drive system according to claim 1 and a skid steer vehicle according to claim 11. Further developments of the invention are defined in the dependent claims.
According to a first aspect of the invention, a steering drive system, particularly a superposition steering drive system, is provided for a skid steer vehicle, wherein the steering .
NYC_MIDT0WN\193998911 314127.000 drive system has: a drive arrangement having a first drive and a second drive which are constructed as separate units, a summing gear unit for summing respective driving torques of the two drives on an output shaft of the summing gear unit, a first drive connection device by means of which the first drive is drivingly connected to a first input shaft of the summing gear unit, and a second drive connection device by means of which the second drive is drivingly connected to a second input shaft of the summing gear unit, wherein the two drive connection devices are arranged in each instance such that no driving torque or back driving torque directed to the drives from the summing gear unit can be transmitted to the drives during a continuously produced drive connection between the drives and the summing gear unit.
Due to the fact that the invention provides two drives, particularly two drives which can be operated simultaneously, whose driving torques are summed by the summing gear unit on a common output shaft, then in the event of failure of one of the drives an emergency steering can be guaranteed by the other respective drive. In case of failure of a drive, a loss of torque for the drive remaining in operation owing to back driving on the inoperative drive is reliably prevented because no driving torque directed to the drives from the summing gear unit can be transmitted to the drives.
In cascaded multi-circuit steering, the drives would have to be overdimensioned. The solution suggested by the invention eliminates this problem through the gear ratio conditions in the summing gear unit. To turn (steer) a skid steer vehicle, a minimum turning torque is required. If there were two cascaded steering drives, for example, then in the event of failure of one drive the drive that is still functioning must apply twice the amount of torque to generate the required turning torque. In the solution according to the invention, the summing gear unit assists the still functioning drive while the second input shaft is inoperative and therefore makes the required turning torque available.
According to an embodiment form of the invention, the first drive and the second drive can be operable independently from one another by means of separate and mutually independent power sources such as, e.g., separate batteries or fuel cells in drives constructed as electric motors or, e.g., separate fuel tanks in drives constructed as combustion engines.
Accordingly, in an advantageous manner the operating reliability and the emergency steering function of the steering drive system are improved even more.
NYC _MI DTOWN\193998911314127.000 According to an embodiment form of the steering drive system according to the invention, the two drive connection devices are self-locking for driving torques directed from the summing gear unit to the drives.
This embodiment of the steering drive system according to the invention can be realized in a particularly simple and therefore economical manner. Further, a steering drive system designed in this way is especially operationally reliable and resistant to failure because the self-locking is triggered without separate signaling or actuating elements whenever driving torque or back drive torque is directed to the drives.
According to embodiment forms of the steering drive system according to the invention, the two drive connection devices each have toothed elements and/or a worm drive and/or a screw drive and/or an epicyclic gear unit.
These embodiments of the steering drive system according to the invention represent additional configurations which can be realized in a simple and therefore economical manner and which are resistant to failure.
According to an embodiment form of the steering drive system according to the invention, the first drive connection device has a first braking device which is arranged to firmly brake a drivetrain of the first drive, the second drive connection device has a second braking device which is arranged to firmly brake a drivetrain of the second drive, and speed detection means are provided for detecting respective driving speeds of the two drives, wherein the braking devices are each arranged to be selectively activated based on the driving speeds of the two drives and a differential speed determined therefrom.
The features according to this embodiment of the invention can be provided additionally or alternatively. The respective braking devices provide an alternative to, or redundancy of; the self-locking which can be controlled and integrated in a simple manner and which is therefore likewise economical. The speed detection means, e.g., contact-based or noncontacting speed sensors, are preferably arranged in the summing gear unit. Further, an electronic control unit can be provided which evaluates speed signals of the speed sensors and determines the differential speed and which is signal-coupled to the braking devices for controlling the latter (switching it on and off).
According to yet another embodiment form of the steering drive system according to the invention, the summing gear unit is a planetary gear unit.
NYC_MIDTOWN\1939989\1314127.000 This embodiment of the summing gear unit provides a technologically proven and reliable possibility for summing two drive outputs. Since there are many commercially available variants of planetary gear units, even standard gear units can be used if required, which further reduces costs and improves service-friendliness, particular with respect to repair times.
The first input shaft of the summing gear unit is preferably drivingly connected directly to a planet carrier of the summing gear unit, the second input shaft of the summing gear unit is drivingly connected directly to a sun gear of the summing gear unit, and the output shaft of the summing gear unit is drivingly connected directly to a ring gear of the summing gear unit.
According to a second aspect of the invention, a skid steer vehicle is provided, particularly a tracked vehicle, which has a steering drive system according to one or more or all of the embodiment forms according to the invention in any conceivable combination and a first steering differential, a second steering differential, a prime mover for realizing a translational drive of the vehicle, and a clutch element, wherein the prime mover is drivingly connected to both steering differentials, and wherein. the clutch element is drivingly connected to both steering differentials and also to the output shaft of the summing gear unit.
The steering differentials and the steering drive system preferably work together in such a way that the clutch element behaves in a neutral manner when the vehicle travels in a straight line, wherein the clutch element is preferably formed by a neutral shaft or zero shaft, and the steering differentials are preferably formed by a planetary gear unit, wherein the zero shaft is stationary when the vehicle drives in a straight line.
The invention will be described in more detail in the following with reference to preferred embodiment forms and the accompanying drawings.
Fig. 1 is a schematic view of a steering drive system of a skid steer vehicle according to the invention.
Fig. 1 shows a schematic view of a driving and steering system I of a skid steer vehicle (not shown in its entirety and not designated separately) constructed in the form of a tracked vehicle according to embodiment forms of the invention.
The skid steer vehicle has a steering drive system 10 and a traction drive system 20, wherein the steering drive system 10 is in a drive connection with the traction drive system 20 to influence the traction drive system 20.
NYC MIDTOWN\1939989\1 314127.000 The steering drive system 10 has a drive arrangement 11 having a first drive 11 a and a second drive 11 b, a summing gear unit 12 constructed as a planetary gear unit or epicyclic gear unit for summing respective driving torques of the two drives I Ia, l lb on an output shaft 13c of the summing gear unit 12, a first drive connection device 14 by means of which the first drive l la is drivingly connected to a first input shaft 13b of the summing gear unit 12, and a second drive connection device 15 by means of which the second drive 11 b is drivingly connected to a second input shaft 13a of the summing gear unit 12.
The first input shaft 13b of the summing gear unit 12 is drivingly connected directly to a planet carrier 12b of the summing gear unit 12, the second input shaft 13a of the summing gear unit 12 is drivingly connected directly to a sun gear 12a of the summing gear unit 12, and the output shaft 13c of the summing gear unit 12 is drivingly connected directly to a ring gear 12c of the summing gear unit 12.
According to embodiment forms of the invention, the first drive 11 a and the second drive I lb are formed, e.g., by an electric motor or a hydraulic motor.
The two drive connection devices 14, 15 are each arranged such that during a continuously produced drive connection (i.e., without the respective drives 1 I a, 11 b being severed or decoupled from the summing gear unit) between the drives l la, l lb and the summing gear unit 12, no driving torque directed to the drives 11a, 11 b from the summing gear unit 12 can be transmitted to the drives I I a, 1 lb.
More precisely stated: the first drive connection device 14 has toothed elements in the form of a self-locking worm drive 14a and a first braking device 14b which is arranged in a drivetrain of the first drive I1 a and in front of the worm drive 14a so that the first braking device 14b when correspondingly controlled can firmly brake the drivetrain of the first drive I I a.
Similarly, the second drive connection device 15 has toothed elements in the form of a self-locking worm drive 15a and a second braking device 15b which is arranged in a drivetrain of the second drive 11 b and in front of the worm drive 15a so that the second braking device 15b can firmly brake the drivetrain of the second drive 1 lb when controlled in a corresponding manner.
Further, the steering drive system 10 has speed detection means, not shown, in the summing gear unit in the form of noncontacting speed sensors for detecting respective driving speeds of the two drives. Further, the steering drive system 10 has an electronic NYC MIDTOWN\1939989\1314127.000 control unit (not shown) which evaluates speed signals of the speed sensors and determines a differential speed therebetween; the control unit is signal-coupled via signal lines, not shown, to the braking devices 14a, 15a for controlling (switching on/switching ofd the latter.
The control unit is configured by hardware and/or software to selectively activate the braking devices 14b, 15b based on their driving speeds and the differential speed so that if one of the drives 11 a, 1 lb fails, its associated braking device 14b or 15b is automatically activated or braked.
The traction drive system 20 has a first steering differential 21 constructed in the form of a planetary gear unit or epicyclic gear unit, a second steering differential 22 constructed in the form of a planetary gear unit or epicyclic gear unit, a prime mover 23, e.g., in the form of a combustion engine or hydraulic motor, for realizing a translational drive of the vehicle, and a clutch element 24 constructed as a zero shaft.
The prime mover 23 is drivingly connected via first input shafts 23a and 23b, respectively, directly to ring gears 21c and 22c, respectively, of the two steering differentials 21, 22. Respective planet carriers 21b and 22b of the two steering differentials 21, 22 are drivingly connected directly to a first driven shaft 25a and a second driven shaft 25b, respectively, for the translational traction drive.
A sun gear 21 a of the first steering differential 21 is drivingly connected via a second input shaft 26a of the first steering differential 21 and via two toothed wheels 26, 27 to a first toothed wheel 24a which is connected to the clutch element 24 so as to be fixed with respect to rotation relative to it. A sun gear 22a of the second steering differential 22 is drivingly connected via a second input shaft 28a of the second steering differential 22 and via a toothed wheel 28 to a second toothed wheel 24b which is connected to the clutch element 24 so as to be fixed with respect to rotation relative to it.
The second toothed wheel 24b which is connected to the clutch element 24 so as to be fixed with respect to rotation relative to it drivingly engages with a toothed wheel 16 which is connected to the output shaft 13c of the summing gear unit 12 so as to be fixed with respect to rotation relative to it.
Although not depicted in this way in Fig. 1, the braking devices 14b, 15b, the speed detection means and the electronic control unit can also be omitted according to embodiment forms of the invention.
NYC MIDTOWN1193998911 314127.000 The operation of the multi-circuit steering system according to embodiment forms of the invention will now be described referring to Fig. 1.
As can be seen from Fig. 1, the prime mover 23 drives into the steering differentials 21, 22 via the first input shafts 23a, 23b and the respective ring gears 21c, 22c. When the vehicle drives in a straight line, the prime mover 23 drives exclusively, the driving torque thereof being distributed to the two driven shafts 25a, 25b via the steering differentials 21, 22.
During synchronous running of the two driven shafts 25a, 25b, the clutch element 24 is stationary or behaves in a neutral manner. When the vehicle corners, a differential torque is generated by the drives 11 a, 11 b of the steering drive system 10, and this differential torque acts on the steering differentials 21, 22 via the drive connection devices 14, 15, via the summing gear unit 12, the toothed wheel 16 arranged on the output shaft 13c of the summing gear unit 12, the clutch element 24 and toothed wheels 26, 27, 28 arranged thereon, and toothed wheels 26, 27, 28 and generates different torques at the driven shafts 25a, 25b. The different torques at the driven shafts 25a, 25b generate a yaw moment which results in different speeds at the driven shafts 25a, 25b and a cornering movement of the vehicle.
The drives 11 a, 11 b of the steering drive system 10 are summed by the summing gear unit 12 in common on the output shaft Be and, therefore, on the toothed wheel 16 arranged thereon. In so doing, the two input shafts 13a, 13b of the summing gear unit 12 are mutually supported by one another with respect to torque.
In the event of failure of one of the drives 11 a, 11 b, this mutual torque-related support is canceled. In so doing, the load direction at the respective worm drive 14a or 15a changes direction, and this change in direction is automatically blocked by the self-locking effect of the worm drive 14a, 15a.
Due to the fixing of one of the input shafts 13a, 13b of the summing gear unit 12, the latter is functionally transformed into a reduction gear unit for the drive l la or 11 b that is still functioning. As a result of the gear ratio conditions in the summing gear unit 12, the toothed wheel 16 of the output shaft Be of the summing gear unit 12, which toothed wheel 16 is drivingly connected to the clutch element 24, is still acted upon by the same nominal torque in spite of the failure of one of the drives 11 a, 11 b.
Accordingly, the vehicle, which possibly needs a high yaw moment to overcome the transverse resistance forces, remains steerable. The failure of one of the drives 1 l a, l l b of NYC MIDTOWN\1939989\1 314127.000 the steering drive system 10 can possibly lead to a reduction in the achievable steering performance, but the vehicle remains steerable.
A firm braking of the inoperative drive l la or 1 lb can also be ensured in addition to or as an alternative to the respective worm drive 14a, 15a by the respective braking device 14b or 15b (if provided). In addition, according to embodiment forms of the invention, secondary states of the drives 11 a, 11 b, e.g., a pressure drop in an inoperative hydrostatic drive 11a or 11 b or the respective speeds and differential speed thereof (as described above), can be used as braking initiators.
NYC MIDTOWN\1939989\1314127.000 Reference Numerals 1 driving and steering system steering drive system 11 drive arrangement h a drive 11 b drive 12 summing gear unit 12a sun gear 12b planet carrier 12c ring gear 13a input shaft 13b input shaft 13c output shaft 14 drive connection device 14a worm drive 14b braking device drive connection device 15a worm drive 15b braking device 16 toothed wheel traction drive system 21 steering differential 21a sun gear 21b planet carrier 21c ring gear 22 steering differential 22a sun gear 22b planet carrier 22c ring gear 23 prime mover 23a input shaft 23b input shaft 24 clutch element NYC-MIDTOWN1193998911 314127.000 24a toothed wheel 24b toothed wheel 25a driven shaft 25b driven shaft 26 toothed wheel 26a input shaft 27 toothed wheel 28 toothed wheel 28a input shaft NYC MIDTOWN\193998911 314127.000
Claims (13)
1. Steering drive system (10) for a skid steer vehicle having: a drive arrangement (11) having a first drive (11a) and a second drive (11b), a summing gear unit (12) for summing respective driving torques of the two drives (11a, 11b) on an output shaft (13c) of the summing gear unit (12), a first drive connection device (14) by means of which the first drive (11a) is drivingly connected to a first input shaft (13b) of the summing gear unit (12), and a second drive connection device (15) by means of which the second drive (11b) is drivingly connected to a second input shaft (13a) of the summing gear unit (12), wherein the two drive connection devices (14, 15) are arranged in each instance such that no driving torque directed to the drives (11a, 11b) from the summing gear unit (12) can be transmitted to the drives (11a, 11b) during a continuously produced drive connection between the drives (11a, 11b) and the summing gear unit (12).
2. Steering drive system (10) according to claim 1, wherein the two drive connection devices (14, 15) are self-locking for driving torques directed from the summing gear unit (12) to the drives (11a, 11b).
3. Steering drive system (10) according to claim 1 or 2, wherein the two drive connection devices (14, 15) each have toothed elements.
4. Steering drive system (10) according to one of claims 1 to 3, wherein the two drive connection devices (14, 15) each have a worm drive (14a, 15a).
5. Steering drive system (10) according to one of claims 1 to 4, wherein the two drive connection devices (14, 15) each have a screw drive.
6. Steering drive system (10) according to one of claims 1 to 5, wherein the two drive connection devices (14, 15) each have an epicyclic gear unit.
7. Steering drive system (10) according to one of claims 1 to 6, wherein the first drive connection device (14) has a first braking device (14b) which is arranged to firmly brake a drivetrain of the first drive (11a), wherein the second drive connection device (15) has a second braking device (15b) which is arranged to firmly brake a drivetrain of the second drive (11b), wherein speed detection means are provided for detecting respective driving speeds of the two drives (11a, 11b), and wherein the braking devices (14b, 15b) are each arranged to be selectively activated based on the driving speeds of the two drives (11a, 11b) and a differential speed determined therefrom.
8. Steering drive system (10) according to claim 7, wherein the speed detection means are arranged in the summing gear unit (12).
9. Steering drive system (10) according to one of claims 1 to 8, wherein the summing gear unit (12) is a planetary gear unit.
10. Steering drive system (10) according to claim 9, wherein the first input shaft (13b) of the summing gear unit (12) is drivingly connected directly to a planet carrier (12b) of the summing gear unit (12), wherein the second input shaft (13a) of the summing gear unit (12) is drivingly connected directly to a sun gear (12a) of the summing gear unit (12), and wherein the output shaft (13c) of the summing gear unit (12) is drivingly connected directly to a ring gear (12c) of the summing gear unit (12).
11. Skid steer vehicle having a steering drive system (10) according to one of claims 1 to 10, a first steering differential (21), a second steering differential (22), a prime mover (23) for realizing a translational drive of the vehicle, and a clutch element (24), wherein the prime mover (23) is drivingly connected to both steering differentials (21, 22), and wherein the clutch element (24) is drivingly connected to both steering differentials (21, 22) and also to the output shaft (13c) of the summing gear unit (12).
12. Skid steer vehicle according to claim 11, wherein the steering differentials (21, 22) and the steering drive system (10) cooperate in such a way that the clutch element (24) behaves in a neutral manner when the vehicle travels in a straight line.
13. Skid steer vehicle according to claim 12, wherein the clutch element (24) is formed by a zero shaft, wherein the steering differentials (21, 22) are respectively formed by a planetary gear unit, and wherein the zero shaft is stationary when the vehicle drives in a straight line.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102009016639A DE102009016639A1 (en) | 2009-04-07 | 2009-04-07 | Steering drive system and thus equipped Radseitengelenktes vehicle |
| DE102009016639.4 | 2009-04-07 | ||
| PCT/DE2009/050068 WO2010115387A1 (en) | 2009-04-07 | 2009-12-08 | Steering drive system and skid steer vehicle equipped therewith |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2785700A1 true CA2785700A1 (en) | 2010-10-14 |
| CA2785700C CA2785700C (en) | 2015-03-24 |
Family
ID=41682518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2785700A Expired - Fee Related CA2785700C (en) | 2009-04-07 | 2009-12-08 | Steering drive system and skid steer vehicle equipped therewith |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US8627907B2 (en) |
| EP (1) | EP2417004A1 (en) |
| KR (1) | KR101324330B1 (en) |
| CA (1) | CA2785700C (en) |
| DE (1) | DE102009016639A1 (en) |
| WO (1) | WO2010115387A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016079556A1 (en) * | 2014-11-20 | 2016-05-26 | Szöllösi Sándor | Energy transducer engine by transforming of turbulent energy |
| CA2988837C (en) | 2016-12-14 | 2020-08-25 | Ontario Drive & Gear Limited | All-terrain vehicle |
| CA2967149C (en) | 2016-12-21 | 2024-04-30 | Peter Derek Visscher | Vehicle drive transmission and electrically assisted steering system |
| CN106763635A (en) * | 2016-12-31 | 2017-05-31 | 湖南省农友农业装备股份有限公司 | A kind of transmission mechanism |
| CN110939702B (en) * | 2019-12-18 | 2021-01-08 | 中国北方车辆研究所 | Compound planet row confluence mechanism |
| DE102021107419A1 (en) | 2021-03-24 | 2022-09-29 | Renk Gmbh | Steering drive system of a wheel steered vehicle, wheel steered vehicle and method of operating the same |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE679337C (en) * | 1934-01-05 | 1939-08-03 | Fried Krupp Akt Ges | Drive and steering device for vehicles, especially for caterpillar vehicles |
| DE2009255C3 (en) | 1970-02-27 | 1979-05-23 | Voith Getriebe Kg, 7920 Heidenheim | Speed ratio control for a differential speed steered vehicle |
| DE2446727A1 (en) | 1974-09-30 | 1976-04-15 | Serck Industries Ltd | Steering system for endless chain driven vehicles - has hydraulically braked or driven epicyclic gear steering trim unit |
| DE3202880A1 (en) * | 1982-01-29 | 1983-08-18 | Zahnräderfabrik Renk AG, 8900 Augsburg | DRIVE SYSTEM FOR DRIVING AND STEERING VEHICLES BY CONTROLLING THE SPEED OF THE DRIVE WHEELS |
| US4998591A (en) * | 1987-08-24 | 1991-03-12 | Renk Aktiengesellschaft | Electro-mechanical drive system for a full-track vehicle |
| WO1989003335A1 (en) * | 1987-10-09 | 1989-04-20 | Zahnradfabrik Friedrichshafen Ag | Superimposed steering gear for tracklaying vehicles |
| DE3832529C2 (en) * | 1988-09-24 | 1997-05-28 | Renk Ag | Superimposed steering drive for a caterpillar |
| JPH0262152U (en) * | 1988-10-31 | 1990-05-09 | ||
| DE19718743A1 (en) * | 1997-05-02 | 1998-11-05 | Zahnradfabrik Friedrichshafen | Propulsion system for tracked vehicles |
| DE10246870B3 (en) * | 2002-10-08 | 2004-04-29 | Renk Aktiengesellschaft | Electro-hydrodynamic overlay steering |
| ATE409635T1 (en) * | 2003-12-04 | 2008-10-15 | Renk Ag | ELECTRIC STEERING AND DRIVE SYSTEM FOR A VEHICLE WITH WHEEL SIDE STEERING |
| JP4079185B1 (en) * | 2006-10-31 | 2008-04-23 | トヨタ自動車株式会社 | POWER OUTPUT DEVICE, HYBRID VEHICLE HAVING THE SAME, AND METHOD FOR CONTROLLING POWER OUTPUT DEVICE |
| US7942220B2 (en) * | 2006-12-22 | 2011-05-17 | Caterpillar Inc. | Differential steering control for a continuously variable transmission machine |
-
2009
- 2009-04-07 DE DE102009016639A patent/DE102009016639A1/en not_active Withdrawn
- 2009-12-08 US US13/319,268 patent/US8627907B2/en not_active Expired - Fee Related
- 2009-12-08 KR KR1020117026526A patent/KR101324330B1/en active IP Right Grant
- 2009-12-08 EP EP09805911A patent/EP2417004A1/en not_active Withdrawn
- 2009-12-08 CA CA2785700A patent/CA2785700C/en not_active Expired - Fee Related
- 2009-12-08 WO PCT/DE2009/050068 patent/WO2010115387A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| KR101324330B1 (en) | 2013-10-31 |
| EP2417004A1 (en) | 2012-02-15 |
| WO2010115387A1 (en) | 2010-10-14 |
| US20120205167A1 (en) | 2012-08-16 |
| DE102009016639A1 (en) | 2010-10-14 |
| CA2785700C (en) | 2015-03-24 |
| KR20120005022A (en) | 2012-01-13 |
| US8627907B2 (en) | 2014-01-14 |
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